Electrospraying from nanofluidic capillary slot.

We present here an original electrospray emitter tip based on a nanofluidic capillary slot. The nanofabrication involves focused ion beam etching to form the slot which has a cross-section of 50×300 nm and a length of 4 μm. The liquid is deformed into the nanofluidic capillary slot by capillary action; the electrospray is produced by the application of a low voltage. Using a water–methanol–formic acid solution, we have observed an electrospray onset voltage of 125 V. At a measured electrospray current of 1 nA, the unforced flow-rate is estimated to be 110 pL min-1. [ABSTRACT FROM AUTHOR]